Pulsar’s goal is to provide an easy way to build scalable network programs.
In the Hello world! web server example above, many client
connections can be handled concurrently.
Pulsar tells the operating system (through epoll or select) that it should be
notified when a new connection is made, and then it goes to sleep.

Pulsar uses the multiprocessing module from the standard python library and
it can be configured to run in multi-processing mode, multi-threading mode or
a combination of the two.

Design

Pulsar internals are based on actors primitive. Actors are the atoms
of pulsar’s concurrent computation, they do not share state between them,
communication is achieved via asynchronous inter-process message passing,
implemented using the standard python socket library.

Two special classes of actors are the Arbiter, used as a singleton,
and the Monitor, a manager of several actors performing similar functions.
The Arbiter runs the main eventloop and it controls the life of all actors.
Monitors manage group of actors performing similar functions, You can think
of them as a pool of actors.

More information about design and philosophy in the documentation.

Add-ons

Pulsar checks if some additional libraries are available at runtime, and
uses them to add additional functionalities or improve performance:

setproctitle: if installed, pulsar can use it to change the processes names
of the running application.

psutil: if installed, a system key is available in the dictionary
returned by Actor info method.

Kudos

Pulsar project started as a fork of gunicorn
and since version 0.5 has been implemented on top of asyncio
(tulip and PEP-3156).
Pulsar uses several snippet of code from around the open-source
community, in particular: